This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:
3GPP third generation partnership project
AC access class
ACB access class barring
BCH broadcast channel
BS base station
DL downlink (eNB towards UE)
EAB extended access barring
eNB E-UTRAN Node B (evolved Node B)
EPC evolved packet core
E-UTRAN evolved UTRAN (LTE)
FDMA frequency division multiple access
ID identity
IE information element
IMSI international mobile subscriber identity
IMTA international mobile telecommunications association
ITU-R international telecommunication union-radiocommunication sector
LTE long term evolution of UTRAN (E-UTRAN)
LTE-A LTE advanced
MAC medium access control (layer 2, L2)
MIB master information block
MM/MME mobility management/mobility management entity
MO mobile originated
NodeB base station
OFDMA orthogonal frequency division multiple access
O&M operations and maintenance
PDCP packet data convergence protocol
PHY physical (layer 1, L1)
Rel release
RLC radio link control
RRC radio resource control
RRM radio resource management
SFN system frame number
SGW serving gateway
SIB system information block
SC-FDMA single carrier, frequency division multiple access
TMSI temporary mobile subscriber identity
TTI transmit time interval
UE user equipment, such as a mobile station, mobile node or mobile terminal
UL uplink (UE towards eNB)
UPE user plane entity
UTRAN universal terrestrial radio access network
One modern cellular communication system is known as evolved UTRAN (E-UTRAN, also referred to as UTRAN-LTE or as E-UTRA). In this system the DL access technique is OFDMA, and the UL access technique is SC-FDMA.
One specification of interest is 3GPP TS 36.300 V10.5.0 (2011-09) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2
(Release 10) incorporated by reference herein in its entirety and referred to for simplicity hereafter as 3GPP TS 36.300.
FIG. 1A reproduces FIG. 4.1 of 3GPP TS 36.300 and shows the overall architecture of the E-UTRAN system (Rel-8). The E-UTRAN system includes eNBs, providing the E-UTRAN user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UEs. The eNBs are interconnected with each other by means of an X2 interface. The eNBs are also connected by means of an S1 interface to an EPC, more specifically to a MME by means of a S1 MME interface and to a S-GW by means of a S1 interface. The S1 interface supports a many-to-many relationship between MMEs/S-GWs/and eNBs.
The eNB hosts the following functions:                functions for RRM: RRC, Radio Admission Control, Connection Mobility Control, Dynamic allocation of resources to UEs in both UL and DL (scheduling);        IP header compression and encryption of the user data stream;        selection of a MME at UE attachment;        routing of User Plane data towards the EPC (S-GW);        scheduling and transmission of paging messages (originated from the MME);        scheduling and transmission of broadcast information (originated from the MME or O&M); and        a measurement and measurement reporting configuration for mobility and scheduling.        
Also of interest herein are the further releases of 3GPP LTE (e.g., LTE Rel-10) targeted towards IMT-A systems, referred to herein for convenience simply as LTE-Advanced (LTE-A).
Reference in this regard may be made to 3GPP TR 36.913 V10.0.0 (2011-03) Technical Report 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Requirements for further advancements for Evolved Universal Terrestrial Radio Access (E-UTRA) (LTE-Advanced)(Release 10). Reference can also be made to 3GPP TR 36.912 V10.0.0 (2011-03) Technical Report 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Feasibility study for Further Advancements for E-UTRA (LTE-Advanced) (Release 10).
A goal of LTE-A is to provide significantly enhanced services by means of higher data rates and lower latency with reduced cost. LTE-A is directed toward extending and optimizing the 3GPP LTE Rel-8 radio access technologies to provide higher data rates at lower cost. LTE-A will be a more optimized radio system fulfilling the ITU-R requirements for IMT-Advanced while maintaining backwards compatibility with LTE Rel-8.
In the current 3GPP LTE system the UE may belong to one of 15 different ACs (one of the ACs is reserved emergency calls i.e. AC10). AC0-AC9 are normal access classes and AC11-15 are considered as special ACs (e.g., used by an operator such as when testing a newly deployed cell, or by a government entity, etc.) The use of access class barring (ACB) makes it possible for the network to control network loading by controlling the number of UEs that can access the network during some period of time. This can be beneficial during emergency situations or at other times when a large amount of user traffic can be expected.
The barring procedure for a UE not belonging to one of the special ACs for a current call type (e.g., originating signaling or originating calls) is as follows:
A) The network broadcasts a percentage parameter (ac-BarringFactor) indication. The UE draws a random number and if the number is less than the barring factor access is allowed for that UE otherwise access is not allowed.
B) If the UE is barred then the UE starts a barring timer with “Tbarring”=(0.7+0.6*rand)*ac-BarringTime. In this case ‘rand’ is the random number and ac-BarringTime is a parameter broadcast by the network.
The barring procedure for a UE belonging to a special AC is as follows:
A) The UE is barred if all of the special ACs to which UE belongs are indicated as barred (with a parameter ac-BarringForSpecialAC).
In the case of the UMTS system the network broadcasts a bitmap to indicate which AC(s) is (are) barred and UE randomizes the access in the MAC layer based on a further parameter from the network. Thus in the UMTS system the network does not broadcast barring timer information.
Reference can be made to 3GPP TS 36.331 V10.3.0 (2011-09) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification (Release 10), such as Section 5.3.3 RRC Connection Establishment, and in particular Sections 5.3.3.2 “Initiation” and 5.3.3.11 “Access Barring Check”. Also of interest is Section 6.3.1 “System Information Blocks”. FIG. 1B reproduces a portion of Section 6.3.1 of 3GPP TS 36.331 and shows the SystemInformationBlockType2 and the access barring related parameters.
The information element (IE) SystemInformationBlockType2 contains radio resource configuration information that is common for all UEs. The various fields shown in FIG. 1B are defined as follows in 3GPP TS 36.331.
SystemInformationBlockType2 field descriptionsac-BarringFactorIf the random number drawn by the UE is lower than this value, access isallowed. Otherwise the access is barred. The values are interpreted in therange [0, 1): p00 = 0, p05 = 0.05, p10 = 0.10, . . . , p95 = 0.95. Valuesother than p00 can only be set if all bits of the corresponding ac-BarringForSpecialAC are set to 0.ac-BarringForCSFBAccess class barring for mobile originating CS fallback.ac-BarringForEmergencyAccess class barring for AC 10.ac-BarringForMO-DataAccess class barring for mobile originating calls.ac-BarringForMO-SignallingAccess class barring for mobile originating signalling.ac-BarringForSpecialACAccess class barring for AC 11-15. The first/leftmost bit is for AC 11, thesecond bit is for AC 12, and so on.ac-BarringTimeMean access barring time value in seconds.additionalSpectrumEmissionThe UE requirements related to IE AdditionalSpectrumEmission aredefined in TS 36.101 [42, table 6.2.4.1].mbsfn-SubframeConfigListDefines the subframes that are reserved for MBSFN in downlink.ssac-BarringForMMTEL-VideoService specific access class barring for MMTEL video originating calls.ssac-BarringForMMTEL-VoiceService specific access class barring for MMTEL voice originating calls.ul-BandwidthParameter: transmission bandwidth configuration, NRB, in uplink, seeTS 36.101 [42, table 5.6-1]. Value n6 corresponds to 6 resource blocks,n15 to 15 resource blocks and so on. If for FDD this parameter is absent,the uplink bandwidth is equal to the downlink bandwidth. For TDD thisparameter is absent and it is equal to the downlink bandwidth.ul-CarrierFreqFor FDD: If absent, the (default) value determined from the defaultTX-RX frequency separation defined in TS 36.101 [42, table 5.7.3-1]applies.For TDD: This parameter is absent and it is equal to the downlinkfrequency.
FIG. 1C shows the Master Information Block contents from 3GPP TS 36.331. The systemFrameNumber element defines the 8 most significant bits of the SFN. As indicated in 3GPP TS 36.211 the 2 least significant bits of the SFN are acquired implicitly in the P-BCH decoding, i.e., timing of 40 ms P-BCH TTI indicates 2 least significant bits (within 40 ms P-BCH TTI, the first radio frame: 00, the second radio frame: 01, the third radio frame: 10, the last radio frame: 11). One value applies for all serving cells (the associated functionality is common i.e. not performed independently for each cell).